Generation and Validation of the Patient-Reported Outcome Measurement Information System Itch Questionnaire–Child (PIQ-C) to Measure the Impact of Itch on Life Quality

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Itch compromises QOL, but most itch assessments focus only on itch intensity. We aimed to develop and validate a comprehensive Patient-Reported Outcomes Measurement Information System (PROMIS) pediatric measure for itch symptoms and itch impact, defined as the effect specifically of itch on physical, mental, and social health, all of which can affect life quality. After literature review, concept elicitation and cognitive interviews with parents and children with itch, and repeated content-expert review, an item pool was generated and refined. The pool was calibrated with data from 499 children with pruritus using exploratory and confirmatory factor analyses, item response theory, and item fit analysis. The resultant 45-item bank, PROMIS Itch Questionnaire-Child (PIQ-C), showed good convergent and discriminant validity in 181 children aged 8‒17 years, discriminating children with different levels of severity, and was responsive to change. Strong correlations (rho ≥ 0.60) were observed with pain and sleep measures, and moderate correlations were observed with other pediatric Patient-Reported Outcomes Measurement Information System measures. Patient-Reported Outcomes Measurement Information System Itch Questionnaire-Child comprehensively measures itch intensity and burden, providing an itch-specific alternative for assessing life quality. The independent calibration of each item/question allows for flexibility in generating short forms or computerized adaptive testing for efficient use in research and office practice.